The long name is not system wide unique though, what if "Bob Marley" and "Bob Marley" have the same password, which "Bob Marley" do we log in?

What? You mean unlike every other system* in the universe, "first come first serve, suck it!" doesn't apply to usernames on discourse? At the very least, put that in giant bold letters on the create an account/forgot password thing.

Put another way: if the user name isn't unique, WTF is the point of having it? "Bob Marley" is a name, not a username... seriously....I'm beginning to think that the world really did hit its peak for just about everything in the 1990s and is now in its long decline.

*Possibly a slight hyperbole. And holy crap, have I gotten curmudgeonly in the past few days...

What? You mean unlike every other system* in the universe, "first come first serve, suck it!" doesn't apply to usernames on discourse? At the very least, put that in giant bold letters on the create an account/forgot password thing.

Put another way: if the user name isn't unique, WTF is the point of having it? "Bob Marley" is a name, not a username... seriously....I'm beginning to think that the world really did hit its peak for just about everything in the 1990s and is now in its long decline.

The long name is just a dumb field, like website or profile. You can put anything you want in there. The short name is the unique username in the system. See:

You mean the one that is broken because it only allows 15 characters? Technology is supposed to make things better, not worse!

Edit: Also, if the short name is the "system wide unique" name, why on earth is it editable in the user preferences? Shouldn't it be fixed at account creation time? (Of course, that explains the warning you get about if you change it, it will break @name stuff... I really can't comprehend the thought process behind that design decision.)

Well of course not; that username contains illegal characters. It can only have alphanumerics and underscores. Instead, I recommend upping the limit to 963 characters, so that you can use the entire lyrics to the Tommy Tutone classic, Jenny:

lol. I'm developing a video game and I finally got a login view set up yesterday. It asks for a username and password but the server doesn't actually look up anything, just says "OK" to whatever the client passes in...for now. Anyway, I didn't put a max length on the input fields, naturally my partners/testers ended up with usernames roughly 400 characters long and caused all kinds of in-game rendering issues when displaying usernames.

The long name is just a dumb field, like website or profile. You can put anything you want in there.

Exactly. I put "EXTREMELY MASSIVE PRIAPISMIC DONG" in there, but what would happen if John Holmes wanted to sign up? Which "EXTREMELY MASSIVE PRIAPISMIC DONG" would we sign him in as? I don't want him getting access to all my special moderator powers.

lol. I'm developing a video game and I finally got a login view set up yesterday. It asks for a username and password but the server doesn't actually look up anything, just says "OK" to whatever the client passes in...for now. Anyway, I didn't put a max length on the input fields, naturally my partners/testers ended up with usernames roughly 400 characters long and caused all kinds of in-game rendering issues when displaying usernames.

Always handle data validation first. Otherwise you'll never come back and do it later and you will get ass-bitten by it.